4 # This tool helps me to check the Linux kernel Kconfig option list
5 # against my security hardening preferences for X86_64, ARM64, X86_32, and ARM.
6 # Let the computers do their job!
8 # Author: Alexander Popov <alex.popov@linux.com>
10 # Please don't cry if my Python code looks like C.
13 # N.B Hardening command line parameters:
15 # page_alloc.shuffle=1
16 # iommu=force (does it help against DMA attacks?)
17 # slub_debug=FZ (slow)
18 # init_on_alloc=1 (since v5.3)
19 # init_on_free=1 (since v5.3, otherwise slub_debug=P and page_poison=1)
21 # debugfs=no-mount (or off if possible)
22 # randomize_kstack_offset=1
24 # Mitigations of CPU vulnerabilities:
26 # mitigations=auto,nosmt (nosmt is slow)
30 # spec_store_bypass_disable=on
43 # Hardware tag-based KASAN with arm64 Memory Tagging Extension (MTE):
45 # kasan.stacktrace=off
48 # N.B. Hardening sysctls:
49 # kernel.kptr_restrict=2 (or 1?)
50 # kernel.dmesg_restrict=1 (also see the kconfig option)
51 # kernel.perf_event_paranoid=3
52 # kernel.kexec_load_disabled=1
53 # kernel.yama.ptrace_scope=3
54 # user.max_user_namespaces=0
55 # what about bpf_jit_enable?
56 # kernel.unprivileged_bpf_disabled=1
57 # net.core.bpf_jit_harden=2
59 # vm.unprivileged_userfaultfd=0
60 # (at first, it disabled unprivileged userfaultfd,
61 # and since v5.11 it enables unprivileged userfaultfd for user-mode only)
63 # dev.tty.ldisc_autoload=0
64 # fs.protected_symlinks=1
65 # fs.protected_hardlinks=1
66 # fs.protected_fifos=2
67 # fs.protected_regular=2
69 # kernel.modules_disabled=1
72 # pylint: disable=missing-module-docstring,missing-class-docstring,missing-function-docstring
73 # pylint: disable=line-too-long,invalid-name,too-many-branches,too-many-statements
77 from argparse import ArgumentParser
78 from collections import OrderedDict
81 from .__about__ import __version__
85 def __init__(self, reason, decision, name, expected):
87 self.expected = expected
88 self.decision = decision
94 if self.expected == self.state:
96 elif self.state is None:
97 if self.expected == 'is not set':
98 self.result = 'OK: not found'
100 self.result = 'FAIL: not found'
102 self.result = 'FAIL: "' + self.state + '"'
104 if self.result.startswith('OK'):
108 def table_print(self, _mode, with_results):
109 print('CONFIG_{:<38}|{:^13}|{:^10}|{:^20}'.format(self.name, self.expected, self.decision, self.reason), end='')
111 print('| {}'.format(self.result), end='')
115 def __init__(self, ver_expected):
116 self.ver_expected = ver_expected
121 if self.ver[0] > self.ver_expected[0]:
122 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
124 if self.ver[0] < self.ver_expected[0]:
125 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
127 if self.ver[1] >= self.ver_expected[1]:
128 self.result = 'OK: version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
130 self.result = 'FAIL: version < ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
133 def table_print(self, _mode, with_results):
134 ver_req = 'kernel version >= ' + str(self.ver_expected[0]) + '.' + str(self.ver_expected[1])
135 print('{:<91}'.format(ver_req), end='')
137 print('| {}'.format(self.result), end='')
141 def __init__(self, name):
147 if self.state is None:
148 self.result = 'FAIL: not present'
150 self.result = 'OK: is present'
153 def table_print(self, _mode, with_results):
154 print('CONFIG_{:<84}'.format(self.name + ' is present'), end='')
156 print('| {}'.format(self.result), end='')
159 class ComplexOptCheck:
160 def __init__(self, *opts):
163 sys.exit('[!] ERROR: empty {} check'.format(self.__class__.__name__))
164 if not isinstance(opts[0], OptCheck):
165 sys.exit('[!] ERROR: invalid {} check: {}'.format(self.__class__.__name__, opts))
170 return self.opts[0].name
174 return self.opts[0].expected
178 return self.opts[0].decision
182 return self.opts[0].reason
184 def table_print(self, mode, with_results):
185 if mode == 'verbose':
186 print(' {:87}'.format('<<< ' + self.__class__.__name__ + ' >>>'), end='')
188 print('| {}'.format(self.result), end='')
191 o.table_print(mode, with_results)
194 o.table_print(mode, False)
196 print('| {}'.format(self.result), end='')
199 class OR(ComplexOptCheck):
200 # self.opts[0] is the option that this OR-check is about.
202 # OR(<X_is_hardened>, <X_is_disabled>)
203 # OR(<X_is_hardened>, <old_X_is_hardened>)
207 sys.exit('[!] ERROR: invalid OR check')
209 for i, opt in enumerate(self.opts):
212 if opt.result != 'OK' or i == 0:
213 # Preserve additional explanation of this OK result.
214 # Simple OK is enough only for the main option that
215 # this OR-check is about.
216 self.result = opt.result
218 # Simple OK is not enough for additional checks.
219 self.result = 'OK: CONFIG_{} "{}"'.format(opt.name, opt.expected)
221 self.result = self.opts[0].result
225 class AND(ComplexOptCheck):
226 # self.opts[0] is the option that this AND-check is about.
228 # AND(<suboption>, <main_option>)
229 # Suboption is not checked if checking of the main_option is failed.
230 # AND(<X_is_disabled>, <old_X_is_disabled>)
233 for i, opt in reversed(list(enumerate(self.opts))):
236 self.result = opt.result
239 # This FAIL is caused by additional checks,
240 # and not by the main option that this AND-check is about.
241 # Describe the reason of the FAIL.
242 if opt.result.startswith('FAIL: \"') or opt.result == 'FAIL: not found':
243 self.result = 'FAIL: CONFIG_{} not "{}"'.format(opt.name, opt.expected)
244 elif opt.result == 'FAIL: not present':
245 self.result = 'FAIL: CONFIG_{} not present'.format(opt.name)
247 # This FAIL message is self-explaining.
248 self.result = opt.result
251 sys.exit('[!] ERROR: invalid AND check')
254 def detect_arch(fname, archs):
255 with open(fname, 'r') as f:
256 arch_pattern = re.compile("CONFIG_[a-zA-Z0-9_]*=y")
258 for line in f.readlines():
259 if arch_pattern.match(line):
260 option, _ = line[7:].split('=', 1)
265 return None, 'more than one supported architecture is detected'
267 return None, 'failed to detect architecture'
271 def detect_version(fname):
272 with open(fname, 'r') as f:
273 ver_pattern = re.compile("# Linux/.* Kernel Configuration")
274 for line in f.readlines():
275 if ver_pattern.match(line):
279 ver_numbers = ver_str.split('.')
280 if len(ver_numbers) < 3 or not ver_numbers[0].isdigit() or not ver_numbers[1].isdigit():
281 msg = 'failed to parse the version "' + ver_str + '"'
283 return (int(ver_numbers[0]), int(ver_numbers[1])), None
284 return None, 'no kernel version detected'
287 def construct_checklist(l, arch):
288 modules_not_set = OptCheck('cut_attack_surface', 'kspp', 'MODULES', 'is not set')
289 devmem_not_set = OptCheck('cut_attack_surface', 'kspp', 'DEVMEM', 'is not set') # refers to LOCKDOWN
291 # 'self_protection', 'defconfig'
292 l += [OptCheck('self_protection', 'defconfig', 'BUG', 'y')]
293 l += [OptCheck('self_protection', 'defconfig', 'SLUB_DEBUG', 'y')]
294 l += [OptCheck('self_protection', 'defconfig', 'GCC_PLUGINS', 'y')]
295 l += [OR(OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_STRONG', 'y'),
296 OptCheck('self_protection', 'defconfig', 'CC_STACKPROTECTOR_STRONG', 'y'))]
297 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_KERNEL_RWX', 'y'),
298 OptCheck('self_protection', 'defconfig', 'DEBUG_RODATA', 'y'))] # before v4.11
299 l += [OR(OptCheck('self_protection', 'defconfig', 'STRICT_MODULE_RWX', 'y'),
300 OptCheck('self_protection', 'defconfig', 'DEBUG_SET_MODULE_RONX', 'y'),
301 modules_not_set)] # DEBUG_SET_MODULE_RONX was before v4.11
302 l += [OR(OptCheck('self_protection', 'defconfig', 'REFCOUNT_FULL', 'y'),
303 VerCheck((5, 5)))] # REFCOUNT_FULL is enabled by default since v5.5
304 iommu_support_is_set = OptCheck('self_protection', 'defconfig', 'IOMMU_SUPPORT', 'y')
305 l += [iommu_support_is_set] # is needed for mitigating DMA attacks
306 if arch in ('X86_64', 'ARM64', 'X86_32'):
307 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y')]
308 l += [OptCheck('self_protection', 'defconfig', 'THREAD_INFO_IN_TASK', 'y')]
309 if arch in ('X86_64', 'ARM64'):
310 l += [OptCheck('self_protection', 'defconfig', 'VMAP_STACK', 'y')]
311 if arch in ('X86_64', 'X86_32'):
312 l += [OptCheck('self_protection', 'defconfig', 'MICROCODE', 'y')] # is needed for mitigating CPU bugs
313 l += [OptCheck('self_protection', 'defconfig', 'RETPOLINE', 'y')]
314 l += [OptCheck('self_protection', 'defconfig', 'X86_SMAP', 'y')]
315 l += [OptCheck('self_protection', 'defconfig', 'SYN_COOKIES', 'y')] # another reason?
316 l += [OR(OptCheck('self_protection', 'defconfig', 'X86_UMIP', 'y'),
317 OptCheck('self_protection', 'defconfig', 'X86_INTEL_UMIP', 'y'))]
318 if arch in ('ARM64', 'ARM'):
319 l += [OptCheck('self_protection', 'defconfig', 'STACKPROTECTOR_PER_TASK', 'y')]
321 l += [OptCheck('self_protection', 'defconfig', 'PAGE_TABLE_ISOLATION', 'y')]
322 l += [OptCheck('self_protection', 'defconfig', 'RANDOMIZE_MEMORY', 'y')]
323 l += [AND(OptCheck('self_protection', 'defconfig', 'INTEL_IOMMU', 'y'),
324 iommu_support_is_set)]
325 l += [AND(OptCheck('self_protection', 'defconfig', 'AMD_IOMMU', 'y'),
326 iommu_support_is_set)]
328 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PAN', 'y')]
329 l += [OptCheck('self_protection', 'defconfig', 'ARM64_EPAN', 'y')]
330 l += [OptCheck('self_protection', 'defconfig', 'UNMAP_KERNEL_AT_EL0', 'y')]
331 l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_EL2_VECTORS', 'y'),
332 AND(OptCheck('self_protection', 'defconfig', 'RANDOMIZE_BASE', 'y'),
333 VerCheck((5, 9))))] # HARDEN_EL2_VECTORS was included in RANDOMIZE_BASE in v5.9
334 l += [OptCheck('self_protection', 'defconfig', 'RODATA_FULL_DEFAULT_ENABLED', 'y')]
335 l += [OptCheck('self_protection', 'defconfig', 'ARM64_PTR_AUTH', 'y')]
336 l += [OptCheck('self_protection', 'defconfig', 'ARM64_BTI_KERNEL', 'y')]
337 l += [OR(OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y'),
338 VerCheck((5, 10)))] # HARDEN_BRANCH_PREDICTOR is enabled by default since v5.10
339 l += [OptCheck('self_protection', 'defconfig', 'ARM64_MTE', 'y')]
341 l += [OptCheck('self_protection', 'defconfig', 'CPU_SW_DOMAIN_PAN', 'y')]
342 l += [OptCheck('self_protection', 'defconfig', 'HARDEN_BRANCH_PREDICTOR', 'y')]
344 # 'self_protection', 'kspp'
345 l += [OptCheck('self_protection', 'kspp', 'SECURITY_DMESG_RESTRICT', 'y')]
346 l += [OptCheck('self_protection', 'kspp', 'BUG_ON_DATA_CORRUPTION', 'y')]
347 l += [OptCheck('self_protection', 'kspp', 'DEBUG_WX', 'y')]
348 l += [OptCheck('self_protection', 'kspp', 'SCHED_STACK_END_CHECK', 'y')]
349 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_HARDENED', 'y')]
350 l += [OptCheck('self_protection', 'kspp', 'SLAB_FREELIST_RANDOM', 'y')]
351 l += [OptCheck('self_protection', 'kspp', 'SHUFFLE_PAGE_ALLOCATOR', 'y')]
352 l += [OptCheck('self_protection', 'kspp', 'FORTIFY_SOURCE', 'y')]
353 l += [OptCheck('self_protection', 'kspp', 'DEBUG_LIST', 'y')]
354 l += [OptCheck('self_protection', 'kspp', 'DEBUG_SG', 'y')]
355 l += [OptCheck('self_protection', 'kspp', 'DEBUG_CREDENTIALS', 'y')]
356 l += [OptCheck('self_protection', 'kspp', 'DEBUG_NOTIFIERS', 'y')]
357 l += [OptCheck('self_protection', 'kspp', 'INIT_ON_ALLOC_DEFAULT_ON', 'y')]
358 l += [OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_LATENT_ENTROPY', 'y')]
359 randstruct_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_RANDSTRUCT', 'y')
360 l += [randstruct_is_set]
361 hardened_usercopy_is_set = OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY', 'y')
362 l += [hardened_usercopy_is_set]
363 l += [AND(OptCheck('self_protection', 'kspp', 'HARDENED_USERCOPY_FALLBACK', 'is not set'),
364 hardened_usercopy_is_set)]
365 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG', 'y'),
367 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_ALL', 'y'),
369 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_SHA512', 'y'),
371 l += [OR(OptCheck('self_protection', 'kspp', 'MODULE_SIG_FORCE', 'y'),
372 modules_not_set)] # refers to LOCKDOWN
373 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_STACK_ALL_ZERO', 'y'),
374 OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STRUCTLEAK_BYREF_ALL', 'y'))]
375 l += [OR(OptCheck('self_protection', 'kspp', 'INIT_ON_FREE_DEFAULT_ON', 'y'),
376 OptCheck('self_protection', 'kspp', 'PAGE_POISONING_ZERO', 'y'))]
377 # CONFIG_INIT_ON_FREE_DEFAULT_ON was added in v5.3.
378 # CONFIG_PAGE_POISONING_ZERO was removed in v5.11.
379 # Starting from v5.11 CONFIG_PAGE_POISONING unconditionally checks
380 # the 0xAA poison pattern on allocation.
381 # That brings higher performance penalty.
382 if arch in ('X86_64', 'ARM64', 'X86_32'):
383 stackleak_is_set = OptCheck('self_protection', 'kspp', 'GCC_PLUGIN_STACKLEAK', 'y')
384 l += [stackleak_is_set]
385 l += [OptCheck('self_protection', 'kspp', 'RANDOMIZE_KSTACK_OFFSET_DEFAULT', 'y')]
386 if arch in ('X86_64', 'X86_32'):
387 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '65536')]
388 if arch in ('ARM64', 'ARM'):
389 l += [OptCheck('self_protection', 'kspp', 'DEFAULT_MMAP_MIN_ADDR', '32768')]
390 l += [OptCheck('self_protection', 'kspp', 'SYN_COOKIES', 'y')] # another reason?
392 l += [OptCheck('self_protection', 'kspp', 'ARM64_SW_TTBR0_PAN', 'y')]
394 l += [OptCheck('self_protection', 'kspp', 'PAGE_TABLE_ISOLATION', 'y')]
395 l += [OptCheck('self_protection', 'kspp', 'HIGHMEM64G', 'y')]
396 l += [OptCheck('self_protection', 'kspp', 'X86_PAE', 'y')]
398 # 'self_protection', 'clipos'
399 l += [OptCheck('self_protection', 'clipos', 'DEBUG_VIRTUAL', 'y')]
400 l += [OptCheck('self_protection', 'clipos', 'STATIC_USERMODEHELPER', 'y')] # needs userspace support
401 l += [OptCheck('self_protection', 'clipos', 'EFI_DISABLE_PCI_DMA', 'y')]
402 l += [OptCheck('self_protection', 'clipos', 'SLAB_MERGE_DEFAULT', 'is not set')] # slab_nomerge
403 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_BOOTLOADER', 'is not set')]
404 l += [OptCheck('self_protection', 'clipos', 'RANDOM_TRUST_CPU', 'is not set')]
405 l += [AND(OptCheck('self_protection', 'clipos', 'GCC_PLUGIN_RANDSTRUCT_PERFORMANCE', 'is not set'),
407 if arch in ('X86_64', 'ARM64', 'X86_32'):
408 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_METRICS', 'is not set'),
410 l += [AND(OptCheck('self_protection', 'clipos', 'STACKLEAK_RUNTIME_DISABLE', 'is not set'),
412 if arch in ('X86_64', 'X86_32'):
413 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_DEFAULT_ON', 'y'),
414 iommu_support_is_set)]
416 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU_SVM', 'y'),
417 iommu_support_is_set)]
419 l += [AND(OptCheck('self_protection', 'clipos', 'INTEL_IOMMU', 'y'),
420 iommu_support_is_set)]
422 # 'self_protection', 'maintainer'
423 ubsan_bounds_is_set = OptCheck('self_protection', 'maintainer', 'UBSAN_BOUNDS', 'y') # only array index bounds checking
424 l += [ubsan_bounds_is_set]
425 l += [AND(OptCheck('self_protection', 'maintainer', 'UBSAN_SANITIZE_ALL', 'y'),
426 ubsan_bounds_is_set)]
427 l += [AND(OptCheck('self_protection', 'maintainer', 'UBSAN_TRAP', 'y'),
428 ubsan_bounds_is_set)]
430 # 'self_protection', 'my'
431 l += [OptCheck('self_protection', 'my', 'RESET_ATTACK_MITIGATION', 'y')] # needs userspace support (systemd)
433 l += [AND(OptCheck('self_protection', 'my', 'AMD_IOMMU_V2', 'y'),
434 iommu_support_is_set)]
436 l += [OptCheck('self_protection', 'my', 'SHADOW_CALL_STACK', 'y')] # depends on clang, maybe it's alternative to STACKPROTECTOR_STRONG
437 l += [OptCheck('self_protection', 'my', 'KASAN_HW_TAGS', 'y')]
438 cfi_clang_is_set = OptCheck('self_protection', 'my', 'CFI_CLANG', 'y')
439 l += [cfi_clang_is_set]
440 l += [AND(OptCheck('self_protection', 'my', 'CFI_PERMISSIVE', 'is not set'),
444 if arch in ('X86_64', 'ARM64', 'X86_32'):
445 l += [OptCheck('security_policy', 'defconfig', 'SECURITY', 'y')] # and choose your favourite LSM
447 l += [OptCheck('security_policy', 'kspp', 'SECURITY', 'y')] # and choose your favourite LSM
448 l += [OptCheck('security_policy', 'kspp', 'SECURITY_YAMA', 'y')]
449 l += [OR(OptCheck('security_policy', 'my', 'SECURITY_WRITABLE_HOOKS', 'is not set'),
450 OptCheck('security_policy', 'kspp', 'SECURITY_SELINUX_DISABLE', 'is not set'))]
451 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM', 'y')]
452 l += [OptCheck('security_policy', 'clipos', 'SECURITY_LOCKDOWN_LSM_EARLY', 'y')]
453 l += [OptCheck('security_policy', 'clipos', 'LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY', 'y')]
454 l += [OptCheck('security_policy', 'my', 'SECURITY_SAFESETID', 'y')]
455 loadpin_is_set = OptCheck('security_policy', 'my', 'SECURITY_LOADPIN', 'y')
456 l += [loadpin_is_set] # needs userspace support
457 l += [AND(OptCheck('security_policy', 'my', 'SECURITY_LOADPIN_ENFORCE', 'y'),
460 # 'cut_attack_surface', 'defconfig'
461 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP', 'y')]
462 l += [OptCheck('cut_attack_surface', 'defconfig', 'SECCOMP_FILTER', 'y')]
463 if arch in ('X86_64', 'ARM64', 'X86_32'):
464 l += [OR(OptCheck('cut_attack_surface', 'defconfig', 'STRICT_DEVMEM', 'y'),
465 devmem_not_set)] # refers to LOCKDOWN
467 # 'cut_attack_surface', 'kspp'
468 l += [OptCheck('cut_attack_surface', 'kspp', 'ACPI_CUSTOM_METHOD', 'is not set')] # refers to LOCKDOWN
469 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_BRK', 'is not set')]
470 l += [OptCheck('cut_attack_surface', 'kspp', 'DEVKMEM', 'is not set')] # refers to LOCKDOWN
471 l += [OptCheck('cut_attack_surface', 'kspp', 'COMPAT_VDSO', 'is not set')]
472 l += [OptCheck('cut_attack_surface', 'kspp', 'BINFMT_MISC', 'is not set')]
473 l += [OptCheck('cut_attack_surface', 'kspp', 'INET_DIAG', 'is not set')]
474 l += [OptCheck('cut_attack_surface', 'kspp', 'KEXEC', 'is not set')] # refers to LOCKDOWN
475 l += [OptCheck('cut_attack_surface', 'kspp', 'PROC_KCORE', 'is not set')] # refers to LOCKDOWN
476 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_PTYS', 'is not set')]
477 l += [OptCheck('cut_attack_surface', 'kspp', 'HIBERNATION', 'is not set')] # refers to LOCKDOWN
478 l += [OptCheck('cut_attack_surface', 'kspp', 'IA32_EMULATION', 'is not set')]
479 l += [OptCheck('cut_attack_surface', 'kspp', 'X86_X32', 'is not set')]
480 l += [OptCheck('cut_attack_surface', 'kspp', 'MODIFY_LDT_SYSCALL', 'is not set')]
481 l += [OptCheck('cut_attack_surface', 'kspp', 'OABI_COMPAT', 'is not set')]
482 l += [modules_not_set]
483 l += [devmem_not_set]
484 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'IO_STRICT_DEVMEM', 'y'),
485 devmem_not_set)] # refers to LOCKDOWN
487 l += [OR(OptCheck('cut_attack_surface', 'kspp', 'STRICT_DEVMEM', 'y'),
488 devmem_not_set)] # refers to LOCKDOWN
490 l += [OptCheck('cut_attack_surface', 'kspp', 'LEGACY_VSYSCALL_NONE', 'y')] # 'vsyscall=none'
492 # 'cut_attack_surface', 'grsecurity'
493 l += [OptCheck('cut_attack_surface', 'grsecurity', 'ZSMALLOC_STAT', 'is not set')]
494 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PAGE_OWNER', 'is not set')]
495 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_KMEMLEAK', 'is not set')]
496 l += [OptCheck('cut_attack_surface', 'grsecurity', 'BINFMT_AOUT', 'is not set')]
497 l += [OptCheck('cut_attack_surface', 'grsecurity', 'KPROBES', 'is not set')] # refers to LOCKDOWN
498 l += [OptCheck('cut_attack_surface', 'grsecurity', 'UPROBES', 'is not set')]
499 l += [OptCheck('cut_attack_surface', 'grsecurity', 'GENERIC_TRACER', 'is not set')] # refers to LOCKDOWN
500 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_VMCORE', 'is not set')]
501 l += [OptCheck('cut_attack_surface', 'grsecurity', 'PROC_PAGE_MONITOR', 'is not set')]
502 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USELIB', 'is not set')]
503 l += [OptCheck('cut_attack_surface', 'grsecurity', 'CHECKPOINT_RESTORE', 'is not set')]
504 l += [OptCheck('cut_attack_surface', 'grsecurity', 'USERFAULTFD', 'is not set')]
505 l += [OptCheck('cut_attack_surface', 'grsecurity', 'HWPOISON_INJECT', 'is not set')]
506 l += [OptCheck('cut_attack_surface', 'grsecurity', 'MEM_SOFT_DIRTY', 'is not set')]
507 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEVPORT', 'is not set')] # refers to LOCKDOWN
508 l += [OptCheck('cut_attack_surface', 'grsecurity', 'DEBUG_FS', 'is not set')] # refers to LOCKDOWN
509 l += [OptCheck('cut_attack_surface', 'grsecurity', 'NOTIFIER_ERROR_INJECTION', 'is not set')]
510 l += [AND(OptCheck('cut_attack_surface', 'grsecurity', 'X86_PTDUMP', 'is not set'),
511 OptCheck('cut_attack_surface', 'my', 'PTDUMP_DEBUGFS', 'is not set'))]
513 # 'cut_attack_surface', 'maintainer'
514 l += [OptCheck('cut_attack_surface', 'maintainer', 'DRM_LEGACY', 'is not set')]
515 l += [OptCheck('cut_attack_surface', 'maintainer', 'FB', 'is not set')]
516 l += [OptCheck('cut_attack_surface', 'maintainer', 'VT', 'is not set')]
517 l += [OptCheck('cut_attack_surface', 'maintainer', 'BLK_DEV_FD', 'is not set')]
519 # 'cut_attack_surface', 'grapheneos'
520 l += [OptCheck('cut_attack_surface', 'grapheneos', 'AIO', 'is not set')]
522 # 'cut_attack_surface', 'clipos'
523 l += [OptCheck('cut_attack_surface', 'clipos', 'STAGING', 'is not set')]
524 l += [OptCheck('cut_attack_surface', 'clipos', 'KSM', 'is not set')] # to prevent FLUSH+RELOAD attack
525 # l += [OptCheck('cut_attack_surface', 'clipos', 'IKCONFIG', 'is not set')] # no, IKCONFIG is needed for this check :)
526 l += [OptCheck('cut_attack_surface', 'clipos', 'KALLSYMS', 'is not set')]
527 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_VSYSCALL_EMULATION', 'is not set')]
528 l += [OptCheck('cut_attack_surface', 'clipos', 'MAGIC_SYSRQ', 'is not set')]
529 l += [OptCheck('cut_attack_surface', 'clipos', 'KEXEC_FILE', 'is not set')] # refers to LOCKDOWN (permissive)
530 l += [OptCheck('cut_attack_surface', 'clipos', 'USER_NS', 'is not set')] # user.max_user_namespaces=0
531 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_MSR', 'is not set')] # refers to LOCKDOWN
532 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_CPUID', 'is not set')]
533 l += [OptCheck('cut_attack_surface', 'clipos', 'IO_URING', 'is not set')]
534 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_IOPL_IOPERM', 'is not set')] # refers to LOCKDOWN
535 l += [OptCheck('cut_attack_surface', 'clipos', 'ACPI_TABLE_UPGRADE', 'is not set')] # refers to LOCKDOWN
536 l += [OptCheck('cut_attack_surface', 'clipos', 'EFI_CUSTOM_SSDT_OVERLAYS', 'is not set')]
537 l += [AND(OptCheck('cut_attack_surface', 'clipos', 'LDISC_AUTOLOAD', 'is not set'),
538 PresenceCheck('LDISC_AUTOLOAD'))]
539 if arch in ('X86_64', 'X86_32'):
540 l += [OptCheck('cut_attack_surface', 'clipos', 'X86_INTEL_TSX_MODE_OFF', 'y')] # tsx=off
542 # 'cut_attack_surface', 'lockdown'
543 l += [OptCheck('cut_attack_surface', 'lockdown', 'EFI_TEST', 'is not set')] # refers to LOCKDOWN
544 l += [OptCheck('cut_attack_surface', 'lockdown', 'BPF_SYSCALL', 'is not set')] # refers to LOCKDOWN
545 l += [OptCheck('cut_attack_surface', 'lockdown', 'MMIOTRACE_TEST', 'is not set')] # refers to LOCKDOWN
547 # 'cut_attack_surface', 'my'
548 l += [OptCheck('cut_attack_surface', 'my', 'TRIM_UNUSED_KSYMS', 'y')]
549 l += [OptCheck('cut_attack_surface', 'my', 'MMIOTRACE', 'is not set')] # refers to LOCKDOWN (permissive)
550 l += [OptCheck('cut_attack_surface', 'my', 'LIVEPATCH', 'is not set')]
551 l += [OptCheck('cut_attack_surface', 'my', 'IP_DCCP', 'is not set')]
552 l += [OptCheck('cut_attack_surface', 'my', 'IP_SCTP', 'is not set')]
553 l += [OptCheck('cut_attack_surface', 'my', 'FTRACE', 'is not set')] # refers to LOCKDOWN
554 l += [OptCheck('cut_attack_surface', 'my', 'VIDEO_VIVID', 'is not set')]
555 l += [OptCheck('cut_attack_surface', 'my', 'INPUT_EVBUG', 'is not set')] # Can be used as a keylogger
557 # 'userspace_hardening'
558 if arch in ('X86_64', 'ARM64', 'X86_32'):
559 l += [OptCheck('userspace_hardening', 'defconfig', 'INTEGRITY', 'y')]
561 l += [OptCheck('userspace_hardening', 'my', 'INTEGRITY', 'y')]
563 l += [OptCheck('userspace_hardening', 'defconfig', 'ARM64_MTE', 'y')]
564 if arch in ('ARM', 'X86_32'):
565 l += [OptCheck('userspace_hardening', 'defconfig', 'VMSPLIT_3G', 'y')]
566 if arch in ('X86_64', 'ARM64'):
567 l += [OptCheck('userspace_hardening', 'clipos', 'ARCH_MMAP_RND_BITS', '32')]
568 if arch in ('X86_32', 'ARM'):
569 l += [OptCheck('userspace_hardening', 'my', 'ARCH_MMAP_RND_BITS', '16')]
571 # l += [OptCheck('feature_test', 'my', 'LKDTM', 'm')] # only for debugging!
574 def print_unknown_options(checklist, parsed_options):
576 for opt in checklist:
577 if hasattr(opt, 'opts'):
579 if hasattr(o, 'name'):
580 known_options.append(o.name)
582 known_options.append(opt.name)
583 for option, value in parsed_options.items():
584 if option not in known_options:
585 print('[?] No rule for option {} ({})'.format(option, value))
588 def print_checklist(mode, checklist, with_results):
592 opt = ['CONFIG_'+o.name, o.expected, o.decision, o.reason]
596 print(json.dumps(opts))
603 print('=' * sep_line_len)
604 print('{:^45}|{:^13}|{:^10}|{:^20}'.format('option name', 'desired val', 'decision', 'reason'), end='')
606 print('| {}'.format('check result'), end='')
608 print('=' * sep_line_len)
611 for opt in checklist:
613 if mode == 'show_ok':
614 if not opt.result.startswith('OK'):
616 if mode == 'show_fail':
617 if not opt.result.startswith('FAIL'):
619 opt.table_print(mode, with_results)
621 if mode == 'verbose':
622 print('-' * sep_line_len)
627 fail_count = len(list(filter(lambda opt: opt.result.startswith('FAIL'), checklist)))
629 ok_count = len(list(filter(lambda opt: opt.result.startswith('OK'), checklist)))
631 if mode == 'show_ok':
632 fail_suppressed = ' (suppressed in output)'
633 if mode == 'show_fail':
634 ok_suppressed = ' (suppressed in output)'
636 print('[+] Config check is finished: \'OK\' - {}{} / \'FAIL\' - {}{}'.format(ok_count, ok_suppressed, fail_count, fail_suppressed))
639 def perform_check(opt, parsed_options, kernel_version):
640 if hasattr(opt, 'opts'):
641 # prepare ComplexOptCheck
643 if hasattr(o, 'opts'):
644 # Recursion for nested ComplexOptChecks
645 perform_check(o, parsed_options, kernel_version)
646 if hasattr(o, 'state'):
647 o.state = parsed_options.get(o.name, None)
648 if hasattr(o, 'ver'):
649 o.ver = kernel_version
651 # prepare simple check, opt.state is mandatory
652 if not hasattr(opt, 'state'):
653 sys.exit('[!] ERROR: bad simple check {}'.format(vars(opt)))
654 opt.state = parsed_options.get(opt.name, None)
658 def perform_checks(checklist, parsed_options, kernel_version):
659 for opt in checklist:
660 perform_check(opt, parsed_options, kernel_version)
663 def parse_config_file(parsed_options, fname):
664 with open(fname, 'r') as f:
665 opt_is_on = re.compile("CONFIG_[a-zA-Z0-9_]*=[a-zA-Z0-9_\"]*")
666 opt_is_off = re.compile("# CONFIG_[a-zA-Z0-9_]* is not set")
668 for line in f.readlines():
673 if opt_is_on.match(line):
674 option, value = line[7:].split('=', 1)
675 elif opt_is_off.match(line):
676 option, value = line[9:].split(' ', 1)
677 if value != 'is not set':
678 sys.exit('[!] ERROR: bad disabled config option "{}"'.format(line))
680 if option in parsed_options:
681 sys.exit('[!] ERROR: config option "{}" exists multiple times'.format(line))
684 parsed_options[option] = value
686 return parsed_options
692 # - reporting about unknown kernel options in the config
693 # - verbose printing of ComplexOptCheck items
694 # * json mode for printing the results in JSON format
695 report_modes = ['verbose', 'json', 'show_ok', 'show_fail']
696 supported_archs = ['X86_64', 'X86_32', 'ARM64', 'ARM']
697 parser = ArgumentParser(prog='kconfig-hardened-check',
698 description='A tool for checking the security hardening options of the Linux kernel')
699 parser.add_argument('--version', action='version', version='%(prog)s ' + __version__)
700 parser.add_argument('-p', '--print', choices=supported_archs,
701 help='print security hardening preferences for the selected architecture')
702 parser.add_argument('-c', '--config',
703 help='check the kernel config file against these preferences')
704 parser.add_argument('-m', '--mode', choices=report_modes,
705 help='choose the report mode')
706 args = parser.parse_args()
712 print("[+] Special report mode: {}".format(mode))
714 config_checklist = []
718 print('[+] Config file to check: {}'.format(args.config))
720 arch, msg = detect_arch(args.config, supported_archs)
722 sys.exit('[!] ERROR: {}'.format(msg))
724 print('[+] Detected architecture: {}'.format(arch))
726 kernel_version, msg = detect_version(args.config)
727 if not kernel_version:
728 sys.exit('[!] ERROR: {}'.format(msg))
730 print('[+] Detected kernel version: {}.{}'.format(kernel_version[0], kernel_version[1]))
732 construct_checklist(config_checklist, arch)
733 parsed_options = OrderedDict()
734 parse_config_file(parsed_options, args.config)
735 perform_checks(config_checklist, parsed_options, kernel_version)
737 if mode == 'verbose':
738 print_unknown_options(config_checklist, parsed_options)
739 print_checklist(mode, config_checklist, True)
744 if mode in ('show_ok', 'show_fail'):
745 sys.exit('[!] ERROR: please use "{}" mode for checking the kernel config'.format(mode))
747 construct_checklist(config_checklist, arch)
749 print('[+] Printing kernel security hardening preferences for {}...'.format(arch))
750 print_checklist(mode, config_checklist, False)
756 if __name__ == '__main__':